By adopting mixed-ligand strategy, three Co(II)/Cd(II) metal–organic frameworks were prepared by hydrothermal reactions of Co(II)/Cd(II) acetate with 1,2-phenylenediacetic acid or 1,3-phenylenediacetic acid(1,2-H₂phda/1,3-H₂phda) combining with two imidazolyl/trazol/pyridyl-type tectons, namely, {[Co(1,2-phda)(bip)(H₂O)₂]·0.25H₂O}_n (1), {[Cd_0.5(1,2-phda)_0.5(bip)_0.5(H₂O)_0.5]·0.5H₂O}_n (2) and [Cd₂(1,3-phda)₂(itmb)₂]_n (3) (bip = 3,5-bis(1-imidazoly)pyridine and itmb = 1-(imidazo-1-ly)-4-(1,2,4-trazol-1-ylmethyl)benzene). The single-crystal X-ray diffraction analyses show that three compounds contain various metal(II)-carboxylate motifs, including carboxylate mononuclear (1), carboxylate chain (2), and carboxylate layer (3), which are further extended by two kinds of coligands to afford a vast diversity of the structures from 3-connected {6³}-hcb topology (1), (4,4) grids layer (2) to 6-connected {4^12·6³} pcu topology (3). Furthermore, the photoluminescences of both Cd(II) complexes exhibit highly selective sensing of Fe³⁺ ion through fluorescence quenching, and may be used as a potential Fe³⁺ sensor material.

中文翻译：

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由羧酸和富氮混合配体组成的三种 Co(II)/Cd(II) 金属-有机骨架的合成、结构多样性和选择性发光传感

采用混合配体策略，通过乙酸Co(II)/Cd(II)与1,2-苯二乙酸或1,3-苯二乙酸的水热反应制备了三种Co(II)/Cd(II)金属-有机骨架酸（1,2-H ₂ phda/1,3-H ₂ phda）结合两个咪唑基/三唑基/吡啶基型结构，即{[Co(1,2-phda)(bip)(H ₂ O) ₂ ]·0.25H ₂ O} _n ( 1 ), {[Cd _0.5 (1,2-phda) _0.5 (bip) _0.5 (H ₂ O) _0.5 ]·0.5H ₂ O} _n ( 2 ) 和 [Cd ₂ (1,3-phda) ₂(itmb) ₂ ] _n ( 3 ) (bip = 3,5-双(1-咪唑基)吡啶和itmb = 1-(imidazo-1-ly)-4-(1,2,4-traazol-1-ylmethyl) ）苯）。单晶X射线衍射分析表明，三种化合物含有多种金属(II)-羧酸基团，包括单核羧酸盐( 1 )、羧酸盐链( 2 )和羧酸盐层( 3 )，它们进一步扩展了两种。配体的数量提供了从 3-connected {6 ³ }- hcb拓扑 ( 1) , (4,4) 网格层 ( 2)到 6-connected {4 ^12· 6 ³ } pcu拓扑 ( 3 )。此外，两种 Cd(II) 配合物的光致发光都通过荧光猝灭对 Fe ³⁺离子表现出高度选择性的传感，可用作潜在的 Fe ³⁺传感器材料。